Falls are one of the greatest health risk factors to elderly people. It has been found that around one third of people above the age of 65 fall at least once a year.
Many of these falls could be avoided by early identification of fall risk and the application of effective and targeted fall prevention programs. Fall prevention trials based on strength and balance training (SBT) have shown that the risk of falling in elderly people can be reduced.
Balance performance measures can be used as early indicators of fall risk and to measure the progress of fall prevention programs. In particular, the Sit-to-Stand (STS) transfer has been identified as an important movement in that respect. Domain experts compare the graph of the power generated during a Sit-To-Stand transfer for fall prevention with the ECG graph in cardiovascular disorders. In daily life, the STS transfer is performed by every person multiple times a day.
Conventionally, only clinical measurement systems (such as those including a force plate and an optical marker system) allow an accurate quantification of power during a sit-to-stand transfer. In these measurement systems, the force plate provides the vertical ground reaction force and the optical marker system provides a measure of displacement in three dimensions. The combination of both measurements is used to quantify the power during a Sit-to-Stand transfer.
These measurement systems have several drawbacks. Firstly, they are clinical equipment, which requires the user to attend a clinic. They are labour intensive to prepare for and perform the measurement (particularly if a number of optical markers need to be attached to specific parts of the body). In addition, they only provide a snapshot of the user's balance performance, where, due to the clinical setting, the user commonly performs beyond average capability. Furthermore, the measurement systems involve a procedure that is quite cumbersome to the user.
There is therefore a need for a method and system for measuring the power used during a vertical movement, such as a sit to stand transfer, that is easy and simple for the user to operate.